Tuning a NFC antenna of a device

ABSTRACT

A NFC object reader&#39;s NFC antenna system configured to dynamically change an element of the NFC antenna system to maintain the NFC antenna system&#39;s antenna default resonant frequency. The NFC antenna system can be configured to include a tuning subsystem, integrated with sensors to trigger tuning of NFC antenna system&#39;s antenna.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/868,247, filed Sep. 28, 2015, entitled, “TUNING A NFC ANTENNA OF ADEVICE,” which is a non-provisional conversion of, and claims priorityto, U.S. Provisional Application No. 62/165,921, filed May 23, 2015,entitled “PAYMENT TERMINAL WITH ACCELEROMETER (SQ-475)—AND—TUNING NFCANTENNAE BASED ON PROXIMITY OF AN NFC ENABLED OBJECT TO THE ANTENNA(SQ-469),” and U.S. application Ser. No. 14/868,247 is a non-provisionalof, and claims priority to, U.S. Provisional Application No. 62/171,175,filed Jun. 4, 2015, entitled “TUNING NFC ANTENNA BASED ON POWER LEVEL OFA POWER SYSTEM OF THE NFC ANTENNA,”; all of which are herebyincorporated by reference herein in their entireties.

BACKGROUND

An introduction of an object into an electromagnetic field can changethe tuning of an antenna's field. The antenna's field can be detuned ordegraded by having a frequency of the antenna's drift away from theresonant frequency of the antenna. For example, within a certaindistance threshold, a NFC enabled object can degrade the tuning of a NFCantenna as the object gets closer to the antenna. The most extreme suchcases is the zero centimeter case—wherein the NFC enabled object is zerocentimeters or adjacent to the NFC antenna, and the NFC antenna detunesthe most.

The detuning of an antenna can have adverse effects to the antenna'sfunction. For example, in the zero centimeter case described above, theNFC antenna requires greater power to read the NFC enabled object.

Detuning of an antenna is exacerbated by smaller antennas, as arecommonly found in mobile payment devices.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe features of the disclosure, a more particulardescription of the presently described technology will be rendered byreference to specific embodiments thereof which are illustrated in theappended drawings. Understanding that these drawings depict only exampleembodiments of the disclosure and are not therefore to be considered tobe limiting of its scope, the principles herein are described andexplained with additional specificity and detail through the use of theaccompanying drawings in which:

FIG. 1 illustrates an example payment communication system for enablingtransactions between merchants and buyers;

FIG. 2 illustrates an example schematic block diagram of the componentsof the payment object reader device;

FIG. 3 illustrates an example circuit diagram for a component of the NFCpayment object reader;

FIG. 4 illustrates the example voltage requirements for a NFC antennasystem to read a NFC enabled object.

FIG. 5 illustrates an example method for tuning a NFC payment objectreader;

FIG. 6 illustrates an example method for tuning a NFC payment objectreader in response to receiving an input from an accelerometer;

FIG. 7 illustrates an example method for tuning a NFC payment objectreader based on input from a proximity sensor;

FIG. 8 is an example perspective view of a wireless payment objectreader with a chip card being inserted;

FIG. 9 is an example perspective view of a wireless payment objectreader with a magnetic stripe card being swiped;

FIG. 10 is an example perspective view of a wireless payment objectreader with a single slot;

FIG. 11 illustrates an example block diagram of components of a merchantPOS device; and

FIG. 12 illustrates an example block diagram of components of a paymentprocessing system.

DETAILED DESCRIPTION

System, devices, methods, and non-transitory computer-readable mediadisclosed in accordance with various embodiments of the presentdisclosure overcome one or more deficiencies in conventional approachesto point of sale systems. In particular, in accordance with variousembodiments, approaches provide for tuning a payment object reader thatis used in performing a payment transaction at a point-of-sale system.

Other advantages, variations, and functions are described and suggestedbelow as can be provided in accordance with the various embodiments.

The present disclosure is for dynamically tuning a NFC antenna by a NFCantenna system in a NFC object reader. Generally, the NFC antennagenerates a default frequency range. The presence of an object withelectromagnetic properties can detune the NFC antenna away from itsdefault frequency range. For example, a NFC enabled object, like a NFCenabled card, when close enough to the NFC antenna, can detune the NFCantenna making the NFC enabled object difficult to read.

As used herein, a financial transaction is a transaction that isconducted between a customer and a merchant at a point-of-sale. Whenpaying for a financial transaction, the customer can provide themerchant with cash, a check, or credit card for the amount that is due.The merchant can interact with a point-of-sale device, e.g., merchantdevice, to process the financial transaction. During financialtransactions, the point-of-sale device can collect data describing thefinancial transaction, including, for example, the amount of paymentreceived from customers.

FIG. 1 illustrates an example architecture of a payment communicationsystem 100 for enabling point-of-sale (POS) transactions betweenmerchants 122 and buyers 126. In the example of FIG. 1, a buyer 126 canuse any of a variety of payment objects, such as payment cards 130, 132or cash 134 when participating in a POS transaction 124 with a merchant122. A buyer 126 can typically have payment cards 130, 132 such ascredit cards, debit cards, prepaid cards, and the like, that the buyer126 can use for conducting a POS transaction 124. In some embodiments,the payment cards 130 can include one or more magnetic stripes forproviding payment object and buyer information when swiped in a paymentobject reader 120 communicatively coupled to a merchant device 116. Insome embodiments, other types of payment objects can be used, forexample smart cards 132 having a built in integrated circuit including amemory chip (e.g., EMV payment objects), a radio frequencyidentification tag (e.g., near field communication enabled objects), andthe like. In some embodiments, the user 126 can use the user device 128to conduct NFC payment transactions through communication between theuser device 128 and the payment object reader/transmitter device 120.

The payment communication system 100 in the example of FIG. 1illustrates a merchant device 116 associated with the merchant 122 thatparticipates in the payment service provided by the service provider ofthe payment processing system 102. The merchant device 116 can be acomputing device (e.g., a mobile computing device) able to communicatewith the payment processing system 102, and with various other computingdevices, through suitable communication protocols, interfaces, andnetworks, including network 114. Further, the merchant device 106 can beany appropriate device operable to send and receive requests, messages,or other types of information over the network 114. Additionally, whileonly a single merchant device 116 is illustrated in the example of FIG.1, in some embodiments there can be additional merchant devicesdepending on the number of merchants participating in the paymentservice, or a plurality of components arranged as a POS system.

Each merchant device 116 can include an instance of a merchantapplication 118 executed on the merchant device. The merchantapplication 118 can provide POS functionality to enable the merchant 122to accept payments at a POS location using the merchant device 116. Insome types of businesses, the POS location can correspond to a store orother place of business of the merchant, and thus, can be a fixedlocation that typically does not change on a day-to-day basis. In othertypes of businesses, however, the POS location can change from time totime, such as in the case that the merchant 122 operates a food truck,is a street vendor, a cab driver, or has an otherwise mobile business,e.g., in the case of merchants who sell items at buyers' homes, buyers'places of business, etc.

The merchant device 116 is communicatively coupled to a payment objectreader 120, either by direct connection, for example through an audiojack of the mobile phone connected to an audio plug of the paymentobject reader, or through wireless connection, such as WiFi, BlueTooth,BLE (Bluetooth low energy), NFC, or other appropriate short-rangecommunication. The payment object reader can read data from a magneticstripe card or an EMV chip-type card and communicate the data to themerchant device 116. The payment object reader can also read data from aNFC device and communicate the data to the merchant device 116.

Accordingly, the merchant 122 and the buyer 126 can conduct a POStransaction 124 by which the buyer 126 acquires an item or service fromthe merchant 122 at a POS location. The merchant application 118 on themerchant device 116 can send transaction information to the paymentprocessing system 102, e.g., as the transaction is being conducted atthe POS location. In some embodiments, such as if a particular merchantdevice 116 is not connected to the network 114 and is thereforeprocessing transactions offline, the transaction information can be sentin a batch at a subsequent point in time or using other suitabletechniques. In some embodiments, the transaction information can be sentvia SMS, MMS, or a voice call.

In some embodiments, the payment processing system 102 is configured tosend and receive data to and from the user device and the merchantdevice. For example, the payment system can be configured to send datadescribing merchants to the user device using, for example, theinformation stored in the merchant account information database 106. Thedata describing merchants can include, for example, a merchant name,geographic location, contact information, and an electronic catalogue,e.g., a menu that describes items that are available for purchase fromthe merchant.

In some embodiments, the payment system can also be configured tocommunicate with a computer system of a card payment network 112, e.g.,MasterCard®, VISA®, etc., over the network, or over a different network,for example, to conduct electronic financial transactions. The computersystem of the card payment network can communicate with a computersystem of a financial institution system 110, e.g., a bank. There can becomputer systems of other entities, e.g., the card acquirer, between thepayment system and the computer system of the card issuer.

The payment system can then communicate with the computer system of acard payment network 112 to complete an electronic financial transactionfor the total amount to be billed to the customer's financial account.Once the electronic financial transaction is complete, the paymentsystem can communicate data describing the card-less payment transactionto the user device, e.g., an electronic receipt, which can, for example,notify the customer of the total amount billed to the user for thecard-less payment transaction with the particular merchant.

The transaction information can include information regarding the time,place, and the amount of each respective transaction, informationrelated to the item acquired, payment card information, as well asadditional information, such as buyer information. For instance, thetransaction information can include data stored in the payment card,e.g., magnetic stripe or integrated circuit data (cardholder name, cardnumber, and other card information). In addition, when completing thetransaction a buyer can sometimes provide a receipt email address forreceiving a receipt through email. Other examples of transactioninformation that can be captured include detailed item information,e.g., an itemized listing of the items or services being acquired, theprice being paid for each item or service, descriptors of the items orservices (e.g., size, flavor, color, etc.), geolocation data indicatinga geographic POS location of a particular transaction, online/offlinecard data, data describing the merchant, e.g., a merchant identifier, amerchant category code (MCC), data describing a buyer, any type of datathat is received upon a buyer's authentication into a social network, ifany, and various other types of information.

To accept electronic payments using the POS system 100, the merchant 122typically creates a merchant account with the payment processing system102 by providing information describing the merchant including, forexample, merchant name, contact information (e.g., telephone numbers,the merchant's address, and one or more financial accounts to whichfunds collected from buyers will be deposited). This merchantinformation can be securely stored by the payment processing system, forexample, as merchant account information 106 in a secure database.Further, the merchant information can include a merchant profile createdfor each merchant. The merchant profile can include information aboutthe merchant 122 and transaction information associated withtransactions conducted by the merchant.

The payment processing system 102 provides a payment service in whichmerchants 122 are able to conduct POS transactions 124 with a pluralityof buyers 126, such as for selling services and/or products to thebuyers 126. The payment processing system 102 can include one or moreservers that are configured to process secure electronic financialtransactions, e.g., payment during a POS transaction 124, bycommunicating with the merchant device 116, card payment networks 112,and bank or other financial institution payment systems 110. The paymentprocessing system 102 includes a payment processing module 108 thatreceives transaction information for processing payments made throughthe merchant application 118. For example, the payment processing module108 can receive transaction information, such as an amount of thetransaction, and can verify that a particular payment card 130, 132 canbe used to pay for the transaction, such as by contacting a cardclearinghouse of a card payment network 112. Furthermore, in someexamples, the payment processing module 108 can redirect paymentinformation for transactions to be made using payment cards 130, 132 toa bank, or other financial institution, payment system 110. In otherembodiments, the merchant device 116 can communicate directly with anappropriate card payment network 112 or bank payment system 110 forapproving or denying a transaction using a particular payment card 130,132 for a POS transaction 124.

As introduced above, the payment processing system 102 can be configuredto communicate with one or more systems of a card payment network 112(e.g., MasterCard®, VISA®, etc) over the network 114 to conductfinancial transactions electronically. The payment processing system 102can also communicate with one or more bank payment systems 110 of one ormore banks over the network 114. For example, the payment processingsystem 102 can communicate with an acquiring bank, a payment cardissuing bank, and/or a bank maintaining buyer accounts for electronicpayments.

A payment card acquiring bank can be a registered member of a cardassociation (e.g., Visa®, MasterCard®, etc), and can be part of a cardpayment network 112. A payment card issuing bank can issue payment cards130, 132 to buyers 126, and can pay acquiring banks for purchases madeby cardholders to which the issuing bank has issued a payment card 130,132. Accordingly, in some embodiments, the systems of an acquiring bankcan be included in the card payment network 112 and can communicate withsystems of a payment card issuing bank to obtain payment. Further, insome embodiments, bank payment systems 110 can include systemsassociated with debit card issuing institutions, in which case, thesystems of the debit card issuing institution can receive communicationsregarding a transaction in which the buyer uses a debit card instead ofa credit card. Additionally, there can be systems of other financialinstitutions involved in some types of transactions or in alternativesystem architectures, and thus, the foregoing are merely severalexamples.

The network 114 can be a conventional type, wired or wireless, and canhave numerous different configurations including a star configuration,token ring configuration, or other configurations. Furthermore, thenetwork 114 can include an intranet, a local area network (LAN), a widearea network (WAN) (e.g., the Internet), and/or other interconnecteddata paths across which multiple devices can communicate. In someembodiments, the network 114 can be a peer-to-peer network. The network114 can also be coupled with or include portions of a telecommunicationsnetwork for sending data using a variety of different communicationprotocols. In some embodiments, the network 114 can include Bluetooth(or Bluetooth low energy) communication networks or a cellularcommunications network for sending and receiving data including viashort messaging service (SMS), multimedia messaging service (MMS),hypertext transfer protocol (HTTP), direct data connection, WAP, email,etc. Although the example of FIG. 1 illustrates one network 114 coupledto the merchant device, payment processing system, card payment network,and bank, more than one network 114 can connect these entities. Thepayment system, the merchant device, and the user device can communicateover the network using wired or wireless connections, or combinationsthereof.

In some embodiments, the payment system is configured to acceptcard-less payment transactions from customers, i.e., the customer 126.As used herein, a card-less payment transaction is a transactionconducted between the customer and a merchant at the point-of-saleduring which a financial account of the customer is charged without thecustomer having to physically present a financial payment card to themerchant at the point-of-sale. In some forms of card-less paymenttransaction, the merchant receives at the point-of-sale details of thefinancial account via the mobile device 128 presenting paymentinformation to the merchant 122 by communicating with the payment objectreader 120, e.g. NFC transactions. In other forms of card-less paymenttransactions, the merchant need not receive any details about thefinancial account at the point-of-sale, e.g., the credit card issuer orcredit card number, for the transaction to be processed. Instead, suchdetails can be stored at the payment processing system 102 and providedto the merchant 122. Such card-less payment transactions can be referredto generally as card-on-file transactions. Generally, when a customerand a merchant enter into an electronic financial transaction, thetransaction is processed by transferring funds from a financial accountassociated with the user account to a financial account associated withthe merchant account.

Before conducting card-less payment transactions of the type that doesnot require that the merchant POS receive financial account details fromcustomer 126, e.g., card-on-file transactions, the customer typicallycreates a user account with the payment system. The customer can createthe user account, for example, by interacting with a user applicationthat is configured to perform card-less payment transactions and that isrunning on the user device. When creating a user account with thepayment system, the customer will provide information of the customer,data describing a financial account of the customer, e.g., credit cardnumber, expiration date, and a billing address. This user informationcan be securely stored by the payment system, for example, in a userinformation database. To accept card-less payment transactions, themerchant typically creates a merchant account with the payment system byproviding information describing the merchant including, for example, amerchant name, contact information, e.g., telephone numbers, themerchant's geographic location address, and one or more financialaccounts to which funds collected from users will be deposited. Thismerchant information can be securely stored by the payment system, forexample, in a merchant information database.

As used herein, the term “payment card,” “payment object,” or “paymentinstrument” refers to a payment mechanism which includes a debit card, aconventional credit card, “smartcards” that have embedded circuits, suchintegrated circuit (IC) cards (e.g., Europay-MasterCard-Visa (EMV)cards), and NFC enabled payment cards, or any wallet-size card whichfunctions as a combination of any of these payment mechanisms. In someembodiments, a payment card, payment object, or payment instrument canalso include a virtual payment card stored on a device such as a smartphone or other device and transmittable, for example, via near fieldcommunication (NFC) or other suitable means.

FIG. 2 illustrates a payment object reader/transmitter device 200 inaccordance with at least some embodiments of the present invention.Payment device 200 includes microcontroller 202 configured to managefunctions between various components within the device. Coupled tomicrocontroller 202 is chip card reader interface 204, which in turn isconnected to card detect switch 206 and card contacts 208. Card contacts208 are configured to provide electrical connectivity between thecontact pads of an integrated circuit enabled payment object and chipcard interface 204. Furthermore, card detect switch 206 is configured toindicate when an integrated circuit payment object is inserted intopayment device 200. Card detect switch 206 may be any suitable switch,electrical, mechanical, or otherwise, and in some embodiments may beintegrated with card contacts 208. In situations where card detectswitch 206 indicates that an integrated circuit payment object has beeninserted into payment device 200, chip card reader interface 204 may beconfigured to read data from the integrated circuit payment object viacard contacts 208.

Payment device 200 may also include a near field communication (NFC)microcontroller 210. NFC microcontroller 210 is configured to manage thetransmission and reception of near field communications through controlof driving circuit 212, NFC modulator 214, NFC RX module 216, NFCantenna monitoring circuit 217, and NFC antenna 218. In someembodiments, driving circuit 212 may include an H-bridge, an amplifier,a filter and/or a matching circuit. Furthermore, in some embodiments theNFC RX module 216 may include an op-amp, a filtering and conditioningcircuit and/or a rectifier, such as a full wave bridge rectifier.Additionally, NFC modulator 214 may be, for example, a type-B modulator.In instances where it is desired to read a NFC enabled payment object,or a NFC enabled payment object is determined to be in proximity topayment device 200, NFC microcontroller 210 may be configured to driveNFC antenna 218 via driving circuit 212 to induce a magnetic fieldcapable of being modulated by the NFC enabled payment object. From here,the modulated magnetic field signal may be converted into a digitalsignal that NFC microcontroller 210 can interpret via NFC RX module 216.On the other hand, when it is desired to transmit data via NFC antenna218, NFC microcontroller 210 may be configured to disable drivingcircuit 212 and transmit data using the NFC protocol by instructing NFCmodulator 214 to modulate the magnetic field to which NFC antenna 218 isoperatively coupled. In some embodiments the NFC antenna 218 can driftor deviate from a desired frequency (become detuned). This can be theresult of a metal object being in the proximity of device 200. The NFCantenna monitor can monitor the frequency of the antenna, and determinewhen the frequency of the antenna has drifted away from the desiredfrequency. When it is determined that the NFC antenna is out of tune,and the tuning algorithm determines that the frequency is outside of atolerance for deviation of the frequency away from a desired frequency,NFC antenna monitor circuit 217 can work in concert with the NFCmicrocontroller to vary one or parameters such as capacitance, voltage,or impedance of the NFC antenna 218 to tune the NFC antenna 218. Thetolerance for a deviation away from the desired frequency of an NFCantenna can be set by the microcontroller of the device so that thefrequency of the NFC antenna cannot deviate more than the tolerance fordeviation with respect to the desired frequency.

To supply power to the components within payment device 200, powersystem 226 is provided. In some embodiments, power system 226 mayinclude a battery. Coupled to power system 226 is USB micro interface228 configured to receive a USB micro jack, although other types ofconnectors may be utilized. In certain embodiments, connection of a jackto USB micro interface 228 can activate a switch within power system 226to override power supplied by the battery. This allows for battery powerto be conserved for situations where external power cannot be provided.Furthermore, power system 226 may also include a battery charger toallow the battery to be charged when external power is supplied via USBmicro interface 228. Payment device 200 also includes wake-upelectronics 230 configured to wake-up the device from a low-power stateto an active state in response to detection of a payment object. In someembodiments, wake-up electronics 230 can also power down payment device230 to a low-power state after a predetermined amount of time or aftercompletion of a communication.

In some embodiments the power levels of the power system 226 can triggerdegrading or other tuning the power supplied to NFC antenna 218 toconserve power. For example, when the battery level of the power system226 falls below a threshold level, this can trigger the device to entera power conservation mode where the microcontroller decreases thestrength of the field generated by the NFC antenna 218. The reader isstill able to operate, but by generating a lesser-quality field, lesspower is consumed, and the overall life of the battery can be prolonged.

As shown in FIG. 2, power system 226 is operatively coupled tomicrocontroller 202. In some embodiments microcontroller 202 can detectthe level of power of the power system 226. Based on the power levels ofpower system 226, microcontroller 202 can trigger a decrease in thepower supplied to NFC antenna 218, thereby decreasing the strength ofthe field generated by the NFC antenna. In some embodiments, thestrength of the field generated by the NFC antenna can be accomplishedusing variable capacitors or other capacitive elements to retune thestrength of the field without changing the amount of power supplied tothe NFC antenna 218. At low power levels, when the power level of thepower source is below a predetermined power level threshold, the tuningof the NFC antenna is adjusted to a first mode where a reduced (forexample, 80%) amount of power is supplied to the NFC antenna. In thefirst mode, the microcontroller 202 can trigger the power supplied tothe NFC antenna 218 to be reduced, to thereby generate a weaker fieldfrom the NFC antenna 218. When the field that is generated by the NFCantenna 218 is weakened to account for low power levels of the powersystem 226 of the NFC antenna 218, the payment objects may need to becloser to the reader for an accurate reading, or may need to be placedon or proximate to the reader for slightly longer periods of time whilestill functioning properly. At high power levels, when the power levelof the power source meets or exceeds the predetermined power level, thetuning of the NFC antenna is adjusted to a second mode where anincreased or a full amount of power can be supplied to the NFC antenna.In the second mode, the microcontroller 202 can supply a full strengthof power to the NFC antenna 218 to generate a full strength field. Thepredetermined power level is an amount of power remaining in the powersource, such as a percentage of battery life that remains. Accordingly,when the percentage falls below a threshold (for example the thresholdcan be 10 percent of battery life for a battery), the device enters thefirst low power mode, and when the percentage is above the threshold,the device operates in the second full power mode with the amount ofpower applied to the NFC antenna increased to a greater amount of powerthan in the first mode.

In some embodiments, a predetermined power level threshold can be set indetermining whether microcontroller 202 triggers degrading the powersupplied to the NFC antenna 218. For example, microcontroller 202 candetect whether the power levels of power system 226 are below thepredetermined power level threshold. At power levels below thepredetermined power level, microcontroller 202 can trigger degrading thepower to NFC antenna 218. At power levels at least equal to thepredetermined power level, microcontroller 202 can trigger full strengthpower to NFC antenna 218.

In some embodiments the power levels of power system 226's can go from alow power level back to a high power level. Accordingly, at the detectedlow power level, microcontroller 202 is operating at a low power to theNFC antenna 218. However, when the power level is detected as high, orabove the predetermined power level, microcontroller 202 can triggerincreasing the power to NFC antenna 218 to return to full strength.

The payment device 200 illustrated in FIG. 2 further contains aBluetooth low energy (BLE) interface 222 and a BLE antenna 224 to enableBluetooth communications. In addition, payment device 200 includesanti-tamper module 220 configured to prevent unauthorized tampering withthe device and possible theft or interception of payment information. Incertain embodiments, anti-tamper module may include a wire mesh enclosedwithin payment device 200.

Payment device 200 also includes user interfaces 232 to enhance the userexperience. User interfaces 232 can include, but are not limited to, LEDindicators, buttons and speakers. In some embodiments, speakers and LEDindicators can be used to present audio and visual identifiers oftransaction and device status. In addition, buttons may be configured topower payment device 200 on or off, operate the device or reset thedevice.

In some embodiments, the NFC antenna 214 can be connected to a tuningcircuit. The tuning circuit is shown in FIG. 3, which illustrates a NFCantenna, tuning circuit, and driving circuit. As seen in FIG. 3, circuit300 includes inductors 304 and capacitors 308, variable capacitor 310and bulk capacitor 312 to maintain the default resonant frequency ofantenna 316. Tuning circuit 301 includes variable capacitor 310.Capacitors 306 filter the signal and resistors 314 are bias resistors.Nodes 302 can operatively coupled to NFC microcontroller 210 or a systemmicrocontroller 202 to control the resonant frequency of antenna 316. Insome embodiments, tuning circuit 301 can tune antenna 316 by changingthe capacitance of variable capacitor 310 and compensate for the detunedantenna 316. In some embodiments, the variable capacitor 310 can be aseparate circuit configured to add or remove capacitance to the overalltuning circuit. For instance, an example circuit configured to add orremove capacitance to the overall tuning circuit can be a system of FETswitches and a bank of discrete capacitors. Therefore, when the monitorcircuit 217 determines that the NFC antenna is detuned, it can triggercontroller 210 to cause the system of FET switches to switch in (or out)a bank of capacitors to add (or remove) capacitance to the NFC antennasystem.

For example, monitor circuit 217 can be configured be an inductancemeasuring circuit to detect a change in the inductance of antenna 218.Monitor circuit 217 can also be configured to monitor the frequency ofantenna 218. In some embodiments, monitor circuit 217 can be configuredto be a rectifier operatively coupled to antenna 218 and a voltagecomparator. A rectifier is a component that converts AC voltage to DCvoltage, whereas a voltage comparator compares two voltages. The voltagecomparator can be configured to determine when the rectified frequencyfrom antenna 218 is below the DC equivalent of the AC default resonantfrequency. In some embodiments, monitor circuit 217 can be configured tobe an analog to digital converter (ADC) connected to antenna 218 and amicroprocessor configured monitor the frequency of antenna 218.

FIG. 2 also illustrates example sensors useful in informing device 200about its current environment, use, or state. Accelerometer 236 can beused to detect motion of the device 236. In some embodiments, detectedmotion (acceleration), or lack of detected motion can be interpreted bymicrocontroller 202 to conclude that device 200 is stationary; wasstationary and is now in motion, which may indicate it is being movedtoward a customer; was in motion and now is stationary, which mayindicate that the device is now in a new environment, and the tuning ofantenna should be check; or quick changes in motion might indicate thedevice is in a merchant's pocket, and the device can go into standbymode.

Similarly, proximity detector 234, can be used to determine that apayment object is coming within range of the antenna, which can be usedto activate the chip card reader interface 204 or power up or increasepower output to NFC antenna. In some embodiments, the proximity detector234 can be useful in determining that a payment object is too close tothe NFC antenna 218 and is causing the NFC antenna to be detuned.

In some embodiments, increasing the overall voltage for the drivingcircuit 212 can tune the detuned antenna 218.

FIG. 4 illustrates the example voltage requirements for a NFC antennasystem to read a NFC enabled object. As a NFC enabled object is faraway, greater power requirements are required to increase the reach ofthe magnetic field. The power requirements decrease as the paymentobject gets closer to the device, until the NFC enabled payment objectgets to a distance threshold 400. Once the NFC enabled payment objectpasses this threshold distance as it moves closer to the NFC antenna,the voltage requirements to read the NFC enabled payment object begin toincrease. Additionally, the NFC enabled object begins to detune the NFCantenna as the NFC enabled object passes the distance threshold 400. Inone embodiment, NFC monitor sub system 217 detects the detuned antenna218 and triggers power system 226 to add more power to driving circuit212 to tune detuned antenna 218. In other embodiments, detuned antenna218 is tuned according to other techniques as described herein.

FIG. 5 illustrates an example method for tuning a NFC payment objectreader. In example method 500, at step 502 tuning is initiated upondetection of a triggering event. For example the proximity detector 234can detect a proximate object which can trigger NFC microcontroller 210to cause driving circuit 212 to tune NFC antenna 218. In anotherexample, the triggering event can be an accelerometer 236 detectingmotion

After a triggering event 502, NFC payment object reader determines 504whether the NFC antenna is detuned. For example in FIG. 2, NFCmicrocontroller 210 can be in operative communication with NFC antennamonitor 217 and can detect a detuned NFC antenna 218. Detection of adefault resonant frequency produced by NFC antenna 218 (i.e., theantenna is in tune) can cause method 500 to proceed back to the eventdetection loop 502.

When it is determined that the NFC antenna is detuned, action is takento tune the NFC antenna. In some embodiments the driving circuit 212 cantune the detuned NFC antenna 218 by varying the capacitance of avariable capacitor. In another example, the NFC Antenna Monitor 217 candetect a detuned NFC antenna 218 and can trigger NFC microcontroller 210to cause driving circuit 212 to trigger FET switches to switch in one ormore members of a bank of capacitors to add capacitance to drivingcircuit 212.

In some embodiments, the detected event can be movement. FIG. 6illustrates an example method for tuning a NFC payment object reader inresponse to receiving an input from an accelerometer.

At step 602 the NFC payment object reader detects whether there ismovement. For example, in FIG. 2, accelerometer 236 can detect movement.If the accelerometer 236 does not detect movement, the NFC paymentobject reader sits at the detection step 602.

Once the accelerometer 236 detects movement (an acceleration), the NFCpayment object reader wakes up its subsystems at 604. For example inFIG. 2, accelerometer 236 detects movement and provides an input to thewake up electronics 230 to instruct NFC microcontroller 210 to wake updriving circuit 212.

Since tuning of a NFC antenna while it is in motion can complicate thetuning process due to changing environmental surroundings, step 606 candetect whether the NFC payment object reader is moving. If the NFCpayment object reader is in motion, the method can pause until movementis completed. However, in some embodiments, the tuning process can stillproceed with the accelerometer data being an input into the tuningalgorithm. Such input can be used to trigger a faster resynchronizationrate or shorter timeout of the tuning circuit 208. In any event, thetuning algorithm can be configured to expect potential abnormalitiescreated by the difficulties of tuning a NFC antenna while it is inmotion.

Once the NFC payment object reader has stopped moving, a tuning processcan be initiated. At step 608, NFC antenna system can determine whetherthe NFC antenna is detuned. The NFC microcontroller 210 and the NFCAntenna Monitor 217 can detect whether NFC antenna 218 is detuned. Insome embodiments, NFC microcontroller 210 can directly detect whetherNFC antenna 218 is detuned. If it is detected that the NFC antenna 218is operating as its default resonant frequency, the antenna is in tune,and the method can 612. However, if the antenna 218 is detuned method600 proceeds to step 610.

In some embodiments, NFC antenna 218 is configured to detect whether itis detuned. In such an example, the NFC antenna 218 is excited to itsdefault resonant frequency range and NFC Antenna Monitor 217 monitorsany change in frequency of NFC antenna 218. The presence of a NFCenabled object into the antenna 210's field can cause the antenna'sfrequency to drift away from resonance or detune. The NFC AntennaMonitor 217 can detect a decrease in frequency or detuning of NFCantenna 218 and can trigger the NFC microcontroller 210 to instructdriving circuit 212 to tune detuned NFC antenna 218.

In some embodiments an anti-tamper module 220 can be used to determineor predict that the NFC antenna 218 might be detuned. For example, theanti-tamper module 220 can be a tamper mesh. A tamper mesh can beintegrated with a system and prevent the system from being physicallyaccessed. In some instances, tamper mesh can function like an inductor,and produce its own resonant frequency, similar to that of the NFCantenna's default resonant frequency. Therefore, the presence of a NFCenabled object within the tamper mesh's electromagnetic field, canchange the frequency detected by a sensor connected to the tamper meshand can indicate whether the NFC antenna would likely be detuned. Thesensor connected to the tamper mesh can trigger the NFC antenna systemto tune the NFC antenna.

At step 610 the NFC antenna is tuned. For example in FIG. 2, drivingcircuit 212 can tune detuned NFC antenna 218 by varying the capacitanceof an analog variable capacitor. In another example, NFC Antenna Monitor217 detects a detuned NFC antenna and triggers NFC microcontroller 210to trigger FET switches to switch in one or more members of a bank ofcapacitors to add capacitance to the overall antenna system. In anotherexample, controller 202 can cause an increase in voltage to be suppliedto antenna 210.

As mentioned above, in some embodiments, the event detected, can beproximity of a NFC enabled object near the NFC antenna. In someembodiments, the NFC enabled object can be a NFC enabled card. In someembodiments, the NFC enabled object can be a smart phone. In someembodiments, the object can be a NFC enabled wearable (e.g. a watch, abracelet, etc.).

FIG. 7 illustrates an example method for tuning the NFC payment objectreader based on input from a proximity detector. At step 702 a NFCpayment object reader detects a NFC enabled object. For example, in FIG.2, proximity detector 234 can detect the presence of a NFC enabledobject. In some embodiments the proximity detector 234 can detect ordetermine the distance of the NFC enabled object to the NFC antenna.

The proximity detector 234 can be an infrared sensor, a microwavesensor, an ultrasonic sensor, or a radio-wave sensor, for example. Theproximity detector 234 can also be cameras and a processor to opticallyprocess and detect the distance of a NFC enabled object relative to theNFC antenna using the images captured by the cameras.

In step 704, NFC payment object reader determines whether the NFCantenna is potentially detuned. Generally there is known distancebetween the object and the NFC antenna system, where detuning of the NFCantenna begins. Therefore when proximity detector 234 detects an objecthas passed through a predetermined distance threshold it can trigger theNFC microcontroller 210 to instruct driving circuit 212 to tune 706 NFCantenna 218. In some embodiments, configuration of NFC Antenna Monitor217 can instruct NFC microcontroller 210 to instruct driving circuit 212to change its tuning circuit's capacitance, voltage, or inductanceaccording to the detected distance of the NFC enabled object to the NFCantenna 218 by proximity detector 234.

In some embodiments, the NFC payment reader can include both a proximitydetector and an accelerometer and gain the combined benefits of thesetwo inputs into a NFC tuning algorithm. As described herein a proximitydetector can be useful in determining that a payment object is too closeto the NFC antenna and thus the antenna's properties need to be adjustedto be able to effectively read the payment object. The motion detectorcan be useful as an input into the tuning algorithm to take into accountpotential behaviors of the NFC antenna that are consistent with achanging environment within which the NFC antenna is operating.

Both sensors can also be used to wake the device from a low power state.In some embodiments, the entire device can be powered up upon detectionof movement or card proximity by the accelerometer or proximity sensor,respectively, or selected subsystems can be powered.

Reference is now made to FIGS. 8 and 9. FIG. 8 is an example perspectiveview 800 of a wireless payment device 802 with a smart chip card 804being inserted at a slot 808 of a chip payment object reader interface823. FIG. 9 is an example perspective view 912 of a wireless paymentobject reader 802 with a magnetic stripe card 910 being swiped at agroove 806 of a magnetic stripe reader interface 829 that is opposite tothe chip payment object reader interface 823. In some embodiments, thewireless payment device 800 may omit groove 806 and associated magneticstripe reader interface 829, and provide a single slot 808 for receivingIC payment objects.

The wireless payment device 802 can have a frame that is configured toreceive card insertions or card swipes. The frame can include a topsurface 820, side surfaces 818, and a bottom surface 822. In theimplementations shown in FIGS. 8 and 9, the wireless payment device 802has a frame that is shaped as a thin parallelepiped, e.g., the width ofthe frame (along the top surface 820) is at least five or ten times theheight (along the side surfaces 818). The top surface and bottom surfacecan be generally shaped as a square or rectangle, e.g., a square orrectangle with rounded edges.

The side surfaces 818 can include one or more openings that receivecards through, respectively, one or more card interfaces. The one ormore card interfaces include circuitry, e.g., chip payment object readercircuitry 828 or magnetic stripe reader circuitry 830, configured toread data stored on the card. In some implementations, the wirelesspayment object reader has two openings on opposite sides of the frame,and a card interface within each opening. In some implementations, thewireless payment device has a single opening with one of the ICinterface, or an MSR interface, or both in a same opening.

The wireless payment object reader 802 can include circuitry configuredto direct signals from the one or more card interfaces, to communicatewirelessly with a computing device, and to efficiently power thewireless payment object reader 802. The one or more card interfaces ofthe wireless payment object reader 802 can include both a chip paymentobject reader interface 823 and a magnetic stripe reader interface 829.In some implementations, the interfaces are on opposite sides of thewireless payment object reader 802 as shown in FIGS. 8-9. In particular,the payment object reader 802 can include both a groove 806 on one sidesurface of the frame and a slot 808 on an opposite side surface of theframe. The groove 806 can extend across the entire width of the frame,and can be configured to receive a swipe of a magnetic stripe card. Themagnetic stripe reader interface 829, including magnetic read heads 832positioned to read the magnetic information on the stripe of the card asit is being swiped, are positioned in the groove 806. The slot 808 canextend across part, but not all of the width of the frame, leaving oneor more thin side walls 824 to constrain the lateral position of a chipcard as it is inserted into the slot 808. The chip payment object readerinterface 823, including electrical contacts 826 positioned toelectrically engage the contacts on the chip card when it is inserted,are positioned in the slot 808.

In alternative implementations, the interfaces are on the same side ofthe wireless payment object reader 802 and share an opening forreceiving smart chip cards and magnetic stripe cards. In someimplementations, a spring-loaded gate is included within the slot 808 ofa chip payment object reader interface 823. The spring-loaded gate canbe configured to engage the electrical contacts 826 with the contacts ofa chip card when a chip card is inserted. On the other hand, thespring-loaded gate keeps the electrical contacts 826 recessed so a cardbeing swiped does not engage with the electrical contacts 826.

In some implementations, the chip payment object reader interface 823 isconfigured to receive an external adapter through the electricalcontacts 826. The external adapter can provide power to recharge thewireless payment object reader 802, e.g., by engaging the electricalcontacts 826. The external adapter can connect the chip payment objectreader interface 823 to a USB port or power supply. The external adaptercan also provide software updates to the wireless payment object reader802.

FIG. 10 illustrates an example perspective view of a wireless paymentdevice 1002 with single slot 1004 for receiving IC payment objects. Insome embodiments, more than one slot can be provided. The device 1002can include a first surface 1006, a side surface 1010, an opposing sidesurface 1011 and a second surface 1012. The payment device 1002 can alsoinclude a front face 1014 and an opposing back face (not shown in FIG.10). In the implementation shown in FIG. 10, the wireless payment device1002 has a frame that is shaped as a thin parallelepiped, e.g., thewidth of the frame (along the first surface 1006) is at least five orten times the height (along the side surface 1010) in some embodiments.The front face 1014 and bottom face can be generally shaped as a squareor rectangle, e.g., a square or rectangle with rounded edges.

The first surface 1006 can include one or more openings that receivecards through, respectively, one or more card interfaces. In theimplementation shown in FIG. 10, the wireless payment device 1002 has asingle slot 1004. The single slot 1004 includes a card interface. Thecard interface can include integrated circuit (IC) chip payment objectreader circuitry. For example the card interface can include a chippayment object reader circuitry for receiving IC payment objects. Thewireless payment device can also have components as shown in FIG. 2. Asshown in FIG. 2, the chip payment card reader, similar to chip cardreader interface 204, can be coupled to a microcontroller, similar tomicrocontroller 202.

Furthermore wireless payment device 1002 may also include NFC relatedcomponents also shown in FIG. 2. For example, similar to FIG. 2,wireless payment device 1002 may also include NFC microcontroller 210.NFC microcontroller 210 is configured to manage the transmission andreception of near field communications through control of drivingcircuit 212, NFC modulator 214, NFC RX module 216, NFC antennamonitoring circuit 217, and NFC antenna 218. In some embodiments, theantenna 217 is disposed internally in the payment device 1002 near thefront face 1014 to facilitate reading NFC enabled payment objectsproximate the front face 1014.

The wireless payment object reader 1002 can include circuitry configuredto direct signals from the one or more card interfaces, to communicatewirelessly with a computing device, and to efficiently power thewireless payment object reader 1002. The slot 1004 can extend acrosspart, but not all of the width of the frame, leaving one or more thinsidewalls to constrain the lateral position of a chip card as it isinserted into the slot 1004 and to prevent rotation of the card while inthe slot. The chip payment object reader interface, including electricalcontacts positioned to electrically engage the contacts on the chip cardwhen it is inserted, are positioned in the slot 1004.

In some implementations, the chip payment object reader interface inslot 1004 is configured to receive an external adapter throughelectrical contacts in wireless payment object reader 1002. The externaladapter can provide power to recharge the wireless payment object reader1002, e.g., by engaging the electrical contacts within slot 1004 ofwireless payment object reader. The external adapter can connect thechip payment object reader interface to a USB port or power supply. Theexternal adapter can also provide software updates to the wirelesspayment object reader 1002.

FIG. 11 is a block diagram illustrating select components of an examplemerchant POS system according to some embodiments. A merchant device1100 can be the merchant device 116 shown in FIG. 1, for example. Themerchant device 1100 can be any suitable type of computing device, e.g.,portable, semi-portable, semi-stationary, or stationary device.

In the example illustrated in FIG. 11, the merchant device 1100 includesat least one processor 1102, a memory 1104, one or more communicationinterfaces 1106, and one or more input/output (I/O) devices 1108. Eachprocessor 1102 can itself comprise one or more processors or processingcores. For example, the processor 1102 can be implemented as one or moremicroprocessors, microcomputers, microcontrollers, digital signalprocessors, central processing units, state machines, logic circuitries,and/or any devices that manipulate signals based on operationalinstructions. In some embodiments, the processor 1102 can be one or morehardware processors and/or logic circuits of any suitable typespecifically programmed or configured to execute the algorithms andprocesses described herein by performing various input/output, logical,and/or mathematical operations. The processor 1102 can be configured tofetch and execute computer-readable processor-executable instructionsstored in the memory 1104.

Other components included in the merchant device 1100 can includevarious types of sensors (not shown), which can include a GPS device, anaccelerometer, gyroscope, compass, proximity detector, and the like.Additionally, the merchant device 1100 can include various othercomponents that are not shown, examples of which include removablestorage, a power source, such as a battery and power control unit, andso forth.

Depending on the configuration of the merchant device 1100, the memory1104 can be an example of non-transitory computer storage media (e.g.,computer-readable media) and can include volatile and nonvolatile memoryand/or removable and non-removable media implemented in any type oftechnology for storage of information such as computer-readableprocessor-executable instructions, data structures, program modules orother data. The computer-readable media can include, but is not limitedto, RAM, ROM, EEPROM, flash memory, solid-state storage, magnetic diskstorage, optical storage, and/or other computer-readable mediatechnology. Further, in some cases, the merchant device 1100 can accessexternal storage, such as RAID storage systems, storage arrays, networkattached storage, storage area networks, cloud storage, or any othermedium that can be used to store information and that can be accessed bythe processor 1102 directly or through another computing device ornetwork. Accordingly, the memory 1104 can be computer storage media ableto store instructions, modules or components that can be executed by theprocessor 1102.

The memory 1104 can be used to store and maintain any number offunctional components or modules that are executable by the processor1102. In some embodiments, these functional components compriseinstructions or programs that are executable by the processor 1102 andthat, when executed, implement operational logic for performing theactions and services attributed above to the merchant device 1100.Functional components of the merchant device 1100 stored in the memory1104 can include a transaction module 1110, a dashboard module 1112, anda security module 1126, although it can also contain modules or portionsof modules assigned herein to the payment processing system 102. Thetransaction module 1110, dashboard module 1112 and security module 1126can all be a part of a merchant application, for example merchantapplication 118, running on merchant device 116. The transaction module1110, for example, presents an interface, such as a payment interface toenable the merchant to conduct transactions, receive payments, and soforth, as well as for communicating with the payment processing system102 for processing payments and sending transaction information. Thedashboard module 1112 enables the merchant to manage the merchant'saccount, the merchant profile, merchant preferences, view saved or newpricing information, communicate with the payment processing system 102regarding cash advances, offers of incentives, invitations, and thelike. The security module 1126 can, as described herein, enable themerchant application to encrypt and decrypt transaction informationcommunicated between the merchant device 1100 and other systemcomponents. Additional functional components can include an operatingsystem 1114 for controlling and managing various functions of themerchant device 1100 and for enabling basic user interactions with themerchant device 1100.

In addition, the memory 1104 can also store data, data structures andthe like, that are used by the functional components. For example, datastored by the memory 1104 can include item information 1116 thatincludes information about the items offered by the merchant, which caninclude a list of items currently available from the merchant, images ofthe items, descriptions of the items, prices of the items, and so forth.For instance, when the merchant 122 is setting up the merchantapplication 118 to accept payments for particular items offered by themerchant 122, the merchant can enter the item information 1116 for theparticular items. Depending on the type of the merchant device 1100, thememory 1104 can also optionally include other functional components anddata, such as other modules and data 1116, which can include programs,drivers, etc., and the data used or generated by the functionalcomponents. Further, the merchant device 1100 can include many otherlogical, programmatic and physical components, of which those describedare merely examples that are related to the discussion herein.

The communication interface(s) 1106 can include one or more interfacesand hardware components for enabling communication with various otherdevices, such as over the network(s) 114 or directly. For example,communication interface(s) 1106 can enable communication through one ormore of the internet, cable networks, wireless networks (e.g., Wi-Fi)and wired networks, as well as close-range communications such asBluetooth®, Bluetooth® low energy, and the like, as additionallyenumerated elsewhere herein.

In another embodiment, the communication interface(s) 1106 can include acellular communications transceiver for sending and receiving data overa cellular communications network such as via voice call, shortmessaging service (SMS), multimedia messaging service (MMS), hypertexttransfer protocol (HTTP), direct data connection, WAP, e-mail or anothersuitable type of electronic communication. The communicationinterface(s) 1106 also provides other conventional connections to thenetwork 114 for distribution of files and/or media objects usingstandard network protocols such as TCP/IP, HTTP, HTTPS and SMTP as willbe understood.

The merchant device 1100 can further include a display 1120, which canemploy any suitable display technology. For example, the display 1120can be a liquid crystal display, a plasma display, a light emittingdiode display, an OLED (organic light-emitting diode) display, anelectronic paper display, or any other suitable type of display able topresent digital content thereon. In some embodiments, the display 1120can have a touch sensor associated with the display 1120 to provide atouchscreen display configured to receive touch inputs for enablinginteraction with a graphical user interface presented on the display1120. Accordingly, embodiments described herein are not limited to anyparticular display technology. Alternatively, in some embodiments, themerchant device 1100 might not include the display 1120, and informationcan be presented by other means, such as aurally.

The merchant device 1100 can further include one or more I/O devices1108. The I/O devices 1108 can include speakers, a microphone, a camera,and various user controls (e.g., buttons, a joystick, a keyboard, akeypad, etc.), a haptic output device, and so forth.

In addition, the merchant device 1100 can include or can be connectableto a payment object reader 1130. In some embodiments, the payment objectreader 1130 can plug in to a port in the merchant device, such as amicrophone/headphone port, a data port, or other suitable port, or cancommunicate via wireless connection to the merchant device. The paymentobject reader 1130 can include a card interface 1106 for reading amagnetic stripe or an integrated circuit of a payment card 130, 132, andfurther can include encryption technology for encrypting the informationread from the payment card 130, 132. Alternatively, numerous other typesof payment object readers 1130 can be employed with the merchant devices1110 herein, depending on the type and configuration of the merchantdevice 1100.

FIG. 12 is a block diagram illustrating select components of an examplepayment processing system 1210 according to some embodiments. Thepayment processing system 1210 can comprise the payment processingsystem 112 in an example embodiment. The payment processing system 1210can be any suitable type of computing device capable of sendingcommunications and performing the functions according to the techniquesdescribed herein and can provide the payment processing service. Forinstance, in the case of a server, the modules, other functionalcomponents, and data can be implemented on a single server, a cluster ofservers, a server farm or data center, a cloud-hosted computing service,a cloud-hosted storage service, and so forth, although other computerarchitectures can additionally or alternatively be used.

Further, while the examples herein illustrate the components and data ofthe payment processing system 1210 as being present in a singlelocation, these components and data can alternatively be distributedacross different computing devices and different locations.Consequently, the functions can be implemented by one or more computingdevices, with the various functionality described above distributed invarious ways across the different computing devices, to collectivelyimplement the payment processing system 1210. Multiple paymentprocessing systems 1210 can be located together or separately, andorganized, for example, as virtual servers, server banks and/or serverfarms. The described functionality can be provided by the servers of asingle entity or enterprise, or can be provided by the servers and/orservices of multiple different buyers or enterprises.

In the example of FIG. 12, the payment processing system 1210 includesone or more processors 1212, one or more memory devices 1214, one ormore communication interfaces 1222, and one or more input/output devices1224. These components can be similar to those described above withreference to FIG. 1 and elsewhere herein.

The memory 1214 can be used to store and maintain any number offunctional components or modules that are executable by the processor1212. In some embodiments, these functional components compriseinstructions or programs that are executable by the processor 1212 andthat, when executed, implement operational logic for performing theactions and services attributed above to the payment processing system1210. Functional components of the payment processing system 1210 storedin the memory 1214 can include the payment processing module 1216, theoperating system 1218, and other modules and data 1220. These componentscan be similar to those described with reference to FIG. 1 and elsewhereherein. In addition, the memory 1214 can store data used for performingthe operations described herein. Thus, the memory 1214 can storemerchant information 1226, including the merchant profiles. Further, thepayment processing system 1210 can include many other logical,programmatic and physical components, of which those described above aremerely examples that are related to the discussion herein.

For clarity of explanation, in some instances the present technology canbe presented as including individual functional blocks includingfunctional blocks comprising devices, device components, steps orroutines in a method embodied in software, or combinations of hardwareand software.

In some embodiments the computer-readable storage devices, mediums, andmemories can include a cable or wireless signal containing a bit streamand the like. However, when mentioned, non-transitory computer-readablestorage media expressly exclude media such as energy, carrier signals,electromagnetic waves, and signals per se.

Methods according to the above-described examples can be implementedusing computer-executable instructions that are stored or otherwiseavailable from computer readable media. Such instructions can comprise,for example, instructions and data which cause or otherwise configure ageneral purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.Portions of computer resources used can be accessible over a network.The computer executable instructions can be, for example, binaries,intermediate format instructions such as assembly language, firmware, orsource code. Examples of computer-readable media that can be used tostore instructions, information used, and/or information created duringmethods according to described examples include magnetic or opticaldisks, flash memory, USB devices provided with non-volatile memory,networked storage devices, and so on.

Devices implementing methods according to these disclosures can comprisehardware, firmware and/or software, and can take any of a variety ofform factors. Typical examples of such form factors include laptops,smart phones, small form factor personal computers, personal digitalassistants, and so on. Functionality described herein also can beembodied in peripherals or add-in cards. Such functionality can also beimplemented on a circuit board among different chips or differentprocesses executing in a single device, by way of further example.

The instructions, media for conveying such instructions, computingresources for executing them, and other structures for supporting suchcomputing resources are means for providing the functions described inthese disclosures.

Although a variety of examples and other information was used to explainaspects within the scope of the appended claims, no limitation of theclaims should be implied based on particular features or arrangements insuch examples, as one of ordinary skill would be able to use theseexamples to derive a wide variety of implementations. Further andalthough some subject matter can have been described in languagespecific to examples of structural features and/or method steps, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to these described features or acts. Forexample, such functionality can be distributed differently or performedin components other than those identified herein. Rather, the describedfeatures and steps are disclosed as examples of components of systemsand methods within the scope of the appended claims.

What is claimed is:
 1. A near field communication (NFC) payment objectreader comprising: a NFC subsystem including an antenna; a powersubsystem that supplies power from a power source to the antenna; and atuning subsystem that tunes the antenna, the tuning subsystem receivinginformation from the power subsystem, wherein based on the informationfrom the power subsystem, the tuning subsystem initiates: a first tuningprocess while the information from the power subsystem indicates that apower level of the power source is below a predetermined power levelthreshold, wherein the power source supplies a first amount of power tothe antenna causing the NFC subsystem to generate a first field with afirst field strength while the antenna is tuned via the first tuningprocess; and a second tuning process while the information from thepower subsystem indicates that the power level of the power sourceexceeds the predetermined power level threshold, wherein the powersource supplies a second amount of power to the antenna causing the NFCsubsystem to generate a second field with a second field strength whilethe antenna is tuned via the second tuning process, wherein the secondamount of power exceeds the first amount of power and the second fieldstrength exceeds the first field strength.
 2. The NFC payment objectreader of claim 1, wherein the first tuning process pauses tuning of theNFC antenna.
 3. The NFC payment object reader of claim 1, wherein thetuning subsystem initiates the first tuning process in response to areduction in the power level of the power source after initiating thesecond tuning process.
 4. The NFC payment object reader of claim 1,wherein the tuning subsystem initiates the second tuning process inresponse to an increase in the power level of the power source afterinitiating the first tuning process.
 5. The NFC payment object reader ofclaim 1, wherein the power subsystem includes the power source.
 6. Anear field communication (NFC) payment object reader comprising: an NFCsubsystem that includes an antenna; a power source that supplies powerto the antenna; and a tuning subsystem that tunes the antenna, whereinthe tuning subsystem tunes the antenna using a first tuning processwhile a power level of the power source is below a predetermined powerlevel threshold, wherein the power source supplies a first amount ofpower to the antenna causing the NFC subsystem to generate a first fieldwith a first field strength while the antenna is tuned via the firsttuning process, wherein the tuning subsystem tunes the antenna using asecond tuning process while the power level of the power source exceedsthe predetermined power level threshold, wherein the power sourcesupplies a second amount of power to the antenna causing the NFCsubsystem to generate a second field with a second field strength whilethe antenna is tuned via the second tuning process, wherein the secondamount of power exceeds the first amount of power and the second fieldstrength exceeds the first field strength.
 7. The NFC payment objectreader of claim 6, wherein the tuning subsystem tunes the antenna usingthe first tuning process in response to a reduction in the power levelof the power source after tuning the antenna using the second tuningprocess.
 8. The NFC payment object reader of claim 6, wherein the tuningsubsystem tunes the antenna using the second tuning process in responseto an increase in the power level of the power source after tuning theantenna using the first tuning process.
 9. The NFC payment object readerof claim 6, further comprising: an electrical contact that receivesexternal power from an external source; and a battery charger that usesthe external power received via the electrical contact to charge arechargeable battery, wherein the power source includes at least therechargeable battery.
 10. The NFC payment object reader of claim 6,wherein the first tuning process is associated with a first tolerancefor deviation from a desired frequency of the NFC subsystem, wherein thesecond tuning process is associated with a second tolerance fordeviation from the desired frequency of the NFC subsystem, and whereinthe first tolerance for deviation from the desired frequency of the NFCsubsystem is greater than the second tolerance for deviation from thedesired frequency.
 11. The NFC payment object reader of claim 6, whereinthe tuning subsystem tunes the antenna more frequently while using thesecond tuning process than while using the first tuning process.
 12. TheNFC payment object reader of claim 6, wherein the tuning subsystemincludes one or more variable capacitors that the tuning subsystem usesto tune a strength of a field generated using the antenna.
 13. A methodof tuning a near field communication (NFC) payment object reader, themethod comprising: identifying a power level of a power source of theNFC payment object reader, wherein the power source supplies power to aNFC antenna; identifying that the power level of the power sourceexceeds a predetermined power level threshold; tuning the NFC antenna ofthe NFC payment object reader according to a first tuning process whilethe power level of the power source exceeds the predetermined powerlevel threshold; supplying a first amount of power to the NFC antennawhile the NFC antenna is tuned via the first tuning process, causing theNFC payment object reader to generate a first field with a first fieldstrength; identifying that the power level of the power source is belowthe predetermined power level threshold; tuning the NFC antenna of theNFC payment object reader according to a second tuning process while thepower level of the power source is below the predetermined power levelthreshold; and supplying a second amount of power to the NFC antennawhile the NFC antenna is tuned via the second tuning process, causingthe NFC payment object reader to generate a second field with a secondfield strength, wherein the first amount of power exceeds the secondamount of power and the first field strength exceeds the second fieldstrength.
 14. The method of claim 13, further comprising: adjusting anamount of capacitance in a tuning circuit, thereby causing the NFCantenna to switch between generating the first field with the firstfield strength and generating the second field with the second fieldstrength.
 15. The method of claim 14, wherein adjusting the amount ofcapacitance in the tuning circuit includes switching one or more fieldeffect transistor (FET) switches to adjust a number of capacitorselectrically connected to the tuning circuit.
 16. The method of claim13, wherein identifying that the power level of the power source isbelow the predetermined power level threshold occurs after identifyingthat the power level of the power source exceeds the predetermined powerlevel threshold, and wherein tuning the NFC antenna of the NFC paymentobject reader according to the second tuning process occurs after tuningthe NFC antenna of the NFC payment object reader according to the firsttuning process.
 17. The method of claim 13, wherein identifying that thepower level of the power source exceeds the predetermined power levelthreshold occurs after identifying that the power level of the powersource is below the predetermined power level threshold, and whereintuning the NFC antenna of the NFC payment object reader according to thefirst tuning process occurs after tuning the NFC antenna of the NFCpayment object reader according to the second tuning process.